SlamDunk. It's because I play basketball.
I bought the first 4 volumes out of an american comic book store. The front covers hooked me so much.[It's hard for me to buy any DC or Marvel comics. They wedge too many stories within the stories. Too many authors and artists for one freaking super hero. No consistency.]

This one resonated to me for having passion for the game.

This one resonated to me for how the manga itself covering the game for what it is.
Team communication.

This one is just cute.

I only got 4 volumes physically. Wanted to get a hold of all the volumes but I was unsuccessful.
So, I just bought the whole volumes of its manga in a cd on ebay.I was newb back then and there was no site that uploaded SlamDunk.

*Sigh* Sadly, it would be Naruto........... Yeah, I loved it at first. I believe I started reading it not too long after the Chuunin Exaxms aired way back on Toonami. I started to read the manga from there. This was probably around 2006. By the time I got caught up, the Hidan and Kakuzu Arc was just starting. Been reading it weekly ever since. I don't know if I should consider that a good thing in hindsight. Let's just say that there has been a HUGE falling out with that series the past five or so years as it continues to get worse and worse...